Symbasis Between Formation Entalpies, Activation Energies of the Electrical Conductivity in Wüstite and in the Clusters of Its Crystal Lattice

Abstract

It is shown that formation enthalpy and activation energy of the electrical conductivity in stoichiometric wüstite can be estimated with the methods of quantum chemistry using the properties of its clusters. The clusters are represented by crystal lattice fragments with fixed or optimized geometric parameters. The formation enthalpy is determined by extrapolating the energy of clusters according to the formulas of simple theories of clusters. The activation energy of electrical conductivity is calculated from relative total energies of formula units for various spin states of wüstite clusters. Calculations were performed with efficient quantum chemical methods PM7 and PBE/sbk which were chosen according to test calculations of bonding and ionization energies for the ground states of the iron atom, its ions, and some of its compounds. The results are in satisfactory agreement with experimental literature data.